Trimming attachment for sewing machines



Oct. 12 1926.

W. C. CARD, JR

TRIMMING ATTACHMENT FOR SEWING MACHINES Filed March 9, 1926 I7. 2v 6 7 21 0 WZZz'a/W 2/ 6'. Cal/TM is produced which Patented "2, H1526.

/VTLLIAM C. CARD, 31%., OF BUSTON, MASSACHUSETTS.

TEMP/LING ATTACHMENT FGR SEVIIIIG DIACHINES.

Application filed March 9, 1926. Serial No. 93,422.

This invention pertains to sewing machine attachments, and more particularly to devices for trimming the edges of the material concomitantlywith the formation of a sewed seam. As one illustration of the utility of such trimming devices reference may be made to the manufactureof footwear where it is a common practice to unite the edge of the outer and inner elements composing certain parts of the upper by means of a seam disposed very close to the edge,trimming off the surplus material of the inner or lining element to produce a neat edge. A further development of this procedure is to provide a beading or binding tape or braid which. covers the exposed edge of the outer element of said part and thus projects over and partially conceals the trimmed edge of the inner or lining element.

Trimmers for performing this operation are well known in the art but the character of the material which must be cut is such that unless the cutting blade be kept very keen at all times ragged or raveling edge greatly lessens the value of the product. In order to keep the blade sufhciently sharp to secure good results, it is usually necessar to sharpen it several times during the ays work, and as each sharpening grinds away some of the blade, care is required in adjusting the blade when it is restored to operative position, while the machine mustnecessarily remain idle during the time required for sharpening.

The principal object of the present inven tion is to provide an arrangementin which the blade is to a certain extent self-sharpening or at least requires sharpening infrequently, and wherein careful readjustment of the blade, each time sharpening does be come desirable, is unnecessary.

In the accompanying drawings, a preferred embodiment of the invention is shown by way of example, and in the drawings:

Fig. 1 is a fragmentary plan view showing certain portions of a sewing machine of cylinder type having theatt-achment embodying; the present invention applied thereto;

Fig. 2 is a fragmentary elevation partly in section on the line 22 of Fig. 1;

Fig. 8 is a perspective view showing the attachment removed from the machine;

Fig. l is a section on the line 47% of Fig 2; and I Fig. 5 is a fragmentary perspective view showing the cutting or trimming blade.

Referring to the drawings for a more detailed description of the mechanism, the numeral l designates the bed or work supporting arm of a sewing machine of cylinder type, such bed being provided with the end member l constituting a housing for a shuttle, looper or other usual stitclrforming element. This housing l is provided with an opening in its upper part adapted to receive the base plate 2 which supports certain parts of the attachment hereinafter more fully described. This base plate is secured to the housing l by means of screws 2 or any other suitable manner. ignates the machine needle and 4t thepresser foot, here shown as of rotary disk type.

The bed 1 supports a horizontally oscillating lever 6, pivoted at 7, and which is oscillated by suitable connections, not shown,

tion of the lever 8 which has the slot 9 is.

resilient so that it may be lifted to disengage the pin from the slot thus permitting the part 8 to be swung to the dotted position indicated at 8 in 1, where it may be held by means of the spring clip 11. When thus disposed the lever 8 remains stationary although the lever 6 may continue to oscillate.

The left-hand arm of the lever 8 is provided with a pair of set screws 12 adapted adjustably to secure the trimmer 13 to the lever 8. The trimmer 13 is provided at its left-hand end as viewed in the with a substantially vertical depending blade portion 14- having a cutting;v edge 15 flush with its left-hand or outer face. The plate M is beveled inwardly from a cutting edge 15 and to sharpen the edge 15 it is only necessary to grind oil a portion of the left-hand or outer surface of the member 14.

The member 9. is provided with a pair of upstanding brackets provided with substantially parallel horizontal guides or supports 16 and 17 (Fig. 3) respectively. These guides or supports are furnished with guideways on their inner opposed surfaces, the guideways preferably being undercut or The numeral 3 desi drawings dovetailed, and adapted to receive slide members 13 and 19 respectively. These slide members 18 and 19 preferably form the spaced, substantially parallel arms of a ll-shaped frame comprising the connecting member 20. The upper surface of the member 20 constitutes a part at least of the work support and is furnished with an opening 21 for the passage of the needle. The member 2 is furnished with slot 22 aligned with the opening 21 to permit the needle to pass downinto the interior of the housing 1 The opening 21 is of a diameter substantially greater than that of the needle so as to permit the U-shaped frame comprising the slides 18 and 19 and the connecting bar 20 to move to a limited extent to right and left.

A bridge piece 23 is secured to the outer ends ofthe guides 16 and 17 by means of screws 24: and supports a bow spring 25 preferably secured at it center to the bridge piece 23 by means of a rivet 26 and having its opposite ends 27 and 28 engaging notches in the ends of the slide members 18 and 19, respectively. The spring 25 thus tends to urge the member 20 to the right.

The right-hand face of the member 20 is preferably Vertical and forms an abutment for engagement with the outer or lefthand face of the blade 1e as the latter is oscillated during tne operation of the machine. To limit the movement of the member 20 under the action of the spring 25 suitable stop means is provided, as for example a pin 31 projecting from the guide member 16 into a recess 32 (Fig. 1) in the slide 18.

The numeral 33 designates the outer member of a composite shoe part, and 3a the corresponding lining element, While 35 designates the ornamental binding braid adapted to cover the edge of the part 33.

In the operation of the device the presser wheel l: holds the work down against the work support 20 and the needle being actuated in usual manner cooperates with the other stitoh-forn'iing elements to form a sewed seam uniting the binding material 35 and the elements 33 and 34. During the operation of the stitch-forming elements the lever 6, together with the auxiliary lever 8, is rapidly oscillated and the cutting edge of the blade l i trims off the projecting edge portion 34 of the lining member 34, leaving the braid 35 projecting slightly beyond the edge of the lining.

The blade 14 oscillates in an arcuate path and at each oscillation rubs against the abut ment surface of the member 20. The friction of the parts tends to wear away the outer surface of the blade 1 and thus to keep the cutting edge 15 sharp, and while the abutment face 29 of the member 20 may also Wear to some extent, it is kept in operat-ive engagement with the blade ii at all times by the spring 25. When the blade becomes worn excessively it may be reset by loosening the screws 12 and then tighten" ing them again after the blade has been properly adjusted.

With the above arrangement much less care is required in readjusting the blade than when the work support is stationary, since the yielding work support takes care of any slight inaccuracies in adjustment of the blade. The close fit of the blade the abutment surface of the member 20 as well as the sharpening action resulting therefrom produces a clean-cut and while with ordinary arrangements it is necessary to sharpen the blade quits frequently the present arrangement permits the blade to be keptin operation for a long period without requiring re-snarpening.

While the invention has been illustrated with reference to a specific embodiment thereof, it is to be understood that various changes in shape, arrangement and proportion of parts may be made without departing from the spirit of the invention, and that in its broader aspects it not limited to the type of cutter employed nor to the specific form ofv sewing machine to which it is applied. As to the latter feature, i is to be understood that while as herein shown the member 2 is curved to fit a machine of cylinder type it is within the scope of the invention to make it flat or of any other suitable shape such as may be necessary to adapt it for mounting upon machines of other kinds.

I claim:

1. sewing machine attachment of the kind having a power driven trimming blade adapted. to trim the edge of the mater'al during the formation of a seam, said attachment comprising a sliding work support provided with an abutment face with which the face of the blade engages, and resilient means urging the work support toward the blade.

2. 1- sewing machine attachment of the kind having a power driven trimming blade :lapted to trim the edge of the material during the formation of a'seam, said attachment comprising a sliding work support provided with a needle opening of a size suilicient to permit limited lateral movement of the support without interference with the needle, said support having a vertical abutment face opposed to the face of the blade, and spring means urging the work support toward the blade.

3. A sewing machine attachment of the kind havingan arm oscillating in a' substantially horizontal plane and provided with a substantially vertical blade portion having a cutting edge flush with its outer face, a;

horizontally sliding work support having a vertical'face opposed to the outer face of the blade, and spring means urging the vertical face of the work support into contact with the vertical face of the blade.

4. A sewing machine attachment of the kind having a substantially vertical and rigid blade moving in an arcuate path about a normally fixed vertical axis, a horizontally slidable work support having a substantially plane vertical abutment face engageable by the blade as the latter moves in its arcuate path, and spring urging the work support toward the blade.

5. A sewing machine attachment of the kind having an oscillating trimmer blade, said blade oscillating about a normally fixed vertical axis, said attachment comprising spaced parallel guides, a work support mounted to slide horizontally in said guides toward and from the path of the blade, a spring urging the work support toward the blade, and means for limiting such move ment.

6. A sewing machine attachment of the kind having a moving trimming blade, said attachment comprising spaced parallel guides, a substantially U-shaped frame having parallel arms respectively engaging said guides and a connecting member, the upper face of the connecting member forming a work support and the outer face of said member being opposed to the face. of the blade, and means tending to move said frame along the guides toward the path of the blade.

7. A sewing machine attachment of the kind having a moving trimming blade, said attachment comprising spaced parallel supports provided with undercut guideways in their opposed faces, a frame having slide members fitting the respective undercut guideways and a member connecting said slide members, said connecting member having a face opposed to the trimming blade and a second face forming a work support, a bridge connecting the spaced supports, and spring means engaging the bridge and the ends of the slides and tending to move the frame toward the path of the blade.

8. A sewing machine attachment of the kind having a moving trimming blade, said attachment comprising spaced parallel supports provided with undercut guideways in their opposed faces, a frame having slide members fitting the respective undercut guideways and a member connecting said slide members, said connecting member having a face opposed to the trimming blade and a second face forming a work support, the connecting member having a hole for the passage of the needle, the hole being of a diameter to permit limited movement of the frame without interference with the needle, a stop limiting movement of the frame, and means urging the frame toward the path of the blade. I

9. A sewing machine attachment of the kind having a moving trimming blade, said attachment comprising spaced parallel sup ports provided with undercut guideways in their opposed faces, a frame having slide members fittin the res ective undercut C) guideways and a member connecting said slide members, said connecting member hav ing a face opposed to the trimming blade and a second face forming a Work support, the connecting member having a passage for the needle, the passage being of a width to permit limited movement of the frame, a pin projecting from one of the spaced supports and engageable with one of the slide members for limiting movement of the frame, and means urging the frame toward the path of the blade.

10. A sewing machine attachment of the kind having a moving trimming blade, said attachment comprising spaced parallel supports provided with undercut guideways in their opposed faces, a frame having slide .members fitting the respective undercut guideways and a member connecting said slide members, said connecting member having a face opposed to the trimming blade and a second face forming a work support, a bridge connecting the spaced supports,

and a bow spring bearing at its central part against the bridge and at its opposite ends against the respective members.

Signed by me at Boston, Massachusetts this 8th day of March 1926.

WILLIAM C. CARD, Jn. 

